1. Field of the Invention
Embodiments of the present invention relate to the operation of semiconductor devices such as microprocessors.
2. Related Art
There are a number of aging and failure mechanisms that can physically affect a semiconductor device (e.g., an integrated circuit or chip such as a microprocessor) and shorten its operating life. Based on studies of those mechanisms, predictions can be made of the effects of the device's operating conditions on the device's operating life. Using those predictions, designers can pick a design operating life and then specify operating limits (e.g., limits on voltage and temperature) that will allow the device to reach its design operating life. The operating limits are enforced during operation to prevent the device from exceeding those limits.
The performance of a device will vary from device to device because of variations that occur during device fabrication (“process” variations). The performance of a device will also vary according to variations in the voltage applied to the device (e.g., its operating voltage) and variations in the device's operating temperature. To account for these variations, a device will generally be operated at less than its capacity, in order to guard against the device exceeding its operating limits. The difference between actual operating conditions and operating limits is sometimes referred to as the guardband.